Apparatus for cooperatively transporting a load

ABSTRACT

An apparatus for transporting a load is described, including: a body including a part or portion for engaging with or connecting to a load to be transported; a ground-engaging device supporting the body, the ground-engaging device for effecting movement of the body over a surface; a transmitter module; a receiver module; and a controller for communicating with the transmitter and receiver modules and the ground engaging device and for receiving status signals from components and/or devices of the apparatus, wherein the controller is capable of conducting a check as to the status of the components and/or devices of the apparatus, and after completing said check to provide an “apparatus operative” or “apparatus non-operative” signal to the transmitter module, wherein the transmitter module is configured to transmit the “apparatus operative” or “apparatus non-operative” signal, and wherein the receiver module is configured to receive from a first predetermined, or designated, other such apparatus its respective “apparatus operative” or “apparatus non-operative” signals.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a 371 of International Application No.PCT/GB2017/052554, filed Sep. 1, 2017, which claims priority to GBPatent Application 1614853.8, filed Sep. 1, 2016, the contents of bothof which are incorporated by reference herein in their entirety.

TECHNICAL FIELD

This invention relates to an apparatus for transporting a load, to asystem for transporting a load and to a method of operating such asystem.

BACKGROUND

More particularly, this invention relates to an apparatus fortransporting a load by pushing or pulling the load over a groundsurface. Such apparatus typically include a ground engaging wheel orwheels which are driven by a motor to effect said movement. Theapparatus is connectable to or engageable with the load so as to moveit. In some prior art systems, heavy loads are moved with the aid of twoor more such apparatus, with the apparatus being connected to the loador being connected to or forming part of a structure (e.g. a frame orthe like) on which the load is supported. In such multiple-apparatussystems, it is necessary to have a coordinated action of the apparatusto move the load.

SUMMARY

According to a first aspect of the invention, we provide an apparatusfor transporting a load, including:

a body including a part or portion for engaging with or connecting to aload to be transported;

a ground-engaging device supporting the body, the ground-engaging devicefor effecting movement of the body over a surface;

a transmitter module;

a receiver module; and

a controller for communicating with the transmitter and receiver modulesand the ground engaging device and for receiving status signals fromcomponents and/or devices of the apparatus,

wherein the controller is capable of conducting a check as to the statusof the components and/or devices of the apparatus, and after completingsaid check to provide an “apparatus operative” or “apparatusnon-operative” signal to the transmitter module,

wherein the transmitter module is configured to transmit the “apparatusoperative” or “apparatus non-operative” signal, and

wherein the receiver module is configured to receive from a firstpredetermined, or designated, other such apparatus its respective“apparatus operative” or “apparatus non-operative” signals.

According to a second aspect of the invention, we provide a system fortransporting a load including at least three apparatus (A, . . . , n−1,n) each in accordance with the first aspect of the invention, and acentral command module for sending movement instructions to move or stopmovement of the ground-engaging device of each apparatus,

wherein the receiver module of each apparatus is configured to receivefrom a first predetermined, or designated, other such apparatus itsrespective “apparatus operative” or “apparatus non-operative” signals.

According to a third aspect of the invention, we provide a method ofoperating the system according to the second aspect of the invention,the method including the steps of:

for each apparatus, conducting a check as to the status of thecomponents and/or devices of the apparatus, and after completing saidcheck providing an “apparatus operative” or “apparatus non-operative”signal to its transmitter module,

for each apparatus, transmitting its “apparatus operative” or “apparatusnon-operative” signal,

for each apparatus, receiving “apparatus operative” or “apparatusnon-operative” signals from a predetermined, or designated, one of theother apparatus,

wherein, if one or more of the apparatus of said system are in an“apparatus non-operative” state, the controller of each apparatus eithershuts down its respective apparatus or ceases to act on any movementinstructions received from the central command module.

Further features of the various aspects of the invention are set out inthe claims appended hereto.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will be described, by way of example only,in accordance with the attached figures, of which:

FIG. 1 is a perspective view of a system in accordance with the secondaspect of the invention;

FIG. 2 is a plan view of the system shown in FIG. 1;

FIG. 3 is an underside view of the system shown in FIG. 1;

FIGS. 4a to 4d are a schematic diagram showing four possible modes ofoperation of the system shown in FIG. 1;

FIG. 5 is a schematic view of the system of FIG. 1 steering in Mode 1;and

FIG. 6 is a schematic diagram showing communication between theapparatus of the system shown in FIG. 1.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Referring to FIGS. 1 to 3, these show a system 1 for transporting aload, including a plurality of apparatus 10 (10 a, 10, 10 c, 10 d, buthereinafter referred to as 10 for ease of reference). In this examplethe system 1 includes four apparatus 10, but it should be appreciatedthat more or fewer apparatus 10 could be used. For instance, two, threeor more apparatuses 10 may be needed to transport a load, or it may bethat twelve apparatuses 10 are needed to transport a load, depending onthe load's weight and dimensions. The number of apparatuses used dependson the weight and size of the load to be transported.

The apparatuses 10 are connected to each other by a frame 2 which inthis example is used to support the load to be transported. The frame 2may be larger or smaller than that which is depicted in the figures. Thesize of frame used may depend on the size and/or the weight of the loadthat needs to be transported. Thus, in some embodiments, the frame maybe significantly larger, with the apparatus 10 spaced much further apartfrom each other. In some embodiments, the apparatus 10 may not bepositioned at the corners of the frame, but may instead be positioned atsome position along the frame between adjacent corners. The frame neednot necessarily be rectangular. It could be triangular or another shape.

In alternative embodiments, the system may not include a frame. In suchembodiments, the apparatus 10 may each engage with or connect to aportion of the load to be transported. Each apparatus 10 may also beequipped with an identification device, such as for example an RFIDdevice. In such an embodiment, the load to be transported may includecorresponding identification devices at the location with which theapparatus 10 engage with or connect to the load. The RFID devicestherefore enable the system to know the location of each apparatus 10 sothat movement of the apparatus 10 can be coordinated accurately to movethe load as desired.

The apparatus 10 includes a body 12 which includes a part or portion 14for engaging with or connecting to a load to be transported. In thepresent embodiment, the part or portion 14 is a part of the frame 2which connects the four apparatuses together. In alternativeembodiments, where the frame is not required, each apparatus 10 may beprovided with a connection formation to connect to the load. This may beby way of a quick release connection or may be semi-permanent, e.g. byway of fasteners. Each apparatus 10 may alternatively have a supportformation upon which a portion of the load is located (or which ispositioned under a portion of the load), and in such embodiments, it maybe necessary for the support formation to be moveable upwardly (manuallyor automatically) so as to transmit a portion of the weight of the loadto the wheel(s) of the apparatus, as is well known in the art.

Each apparatus 10 includes a ground-engaging device 16 supporting thebody 12, the ground-engaging device 16 for effecting movement of thebody 12 over a surface. In the present embodiment the ground-engagingdevice 16 includes a wheel 18 rotatable about a substantially horizontalaxis which is driven by an electric motor 20. A further electric motor22 is provided for effecting steering of the wheel 18. In thisembodiment, the further electric motor 22 is mounted to provide rotationof the support for the wheel 18 about a substantially vertical axis. Thefurther electric motor 22 is provided with an output shaft on which issupported a gear 24 which meshes with a further gear 26 connected to thesupport for the wheel 18. The gears 24, 26 are both mounted in asubstantially horizontal plane and effect rotation of the wheel 18 abouta substantially vertical axis. However, bevel, or crown, gears mayinstead be used to permit the further electric motor 22 to be mounted ina different position.

Referring to FIG. 4, the apparatus 10 are operated synchronously to movethe load as desired. In order to achieve this, coordinated steering anddrive to the wheels 18 of each apparatus 10 is necessary. The fourwheels 18 of the system 1 may move in different modes.

In Mode 1 (see FIGS. 4a and 4b ) the system 1 acts like afour-wheel-steered car. Thus, all four wheels 18 are steered to desiredpositions and driven so as to effect left or right hand steeredmovement. As will be appreciated, the innermost wheels 18 a, 18 b (e.g.those on the left of the system when turning left) are steered to agreater angle than the wheels 18 c, 18 d on the outside. This is shownby way of example in FIG. 5, where C indicates the axis of the turn.

Mode 3 (see FIG. 4c ) permits the load to be rotated. A point betweenall of the apparatuses 10, e.g. a substantially central axis of theload, is selected around which all of the apparatuses 10 rotate. Inorder to achieve this, the direction of each of the wheels 18 must besteered by the motors 22 so that they each point substantiallyperpendicularly to a plane which intersects the central axis of theload. All four wheels 18 can then be driven forwardly or rearwardly toeffect clockwise or anti-clockwise rotation of the load.

In Mode 4 (see FIG. 4d ) the wheels 18 of the apparatuses 10 are allforced, or locked, so as to move in the same direction. This permitslinear translational movement of the load only, in any direction.

Whilst in the present embodiment wheels 18 are used, other types ofground engaging device may also be used. For instance, castor wheels maybe used in combination with fixed wheels to permit steering of theapparatus whilst providing a simpler setup for the motors driving theapparatus. Alternatively, each apparatus may include one or a set ofcaterpillar-like tracks to enable the apparatus 10 to negotiatedifficult surfaces.

As mentioned above, the apparatuses 10 are used as part of a system 1.The system 1 includes a plurality of apparatuses 10 and a centralcommand module (CCM) 4 (described in more detail below), for sendingmovement instructions to move or stop movement of the wheels 18 of eachapparatus 10. Referring to FIG. 6, which shows a schematic of the system1, each of the apparatuses 10 is provided with a movement instructionreceiver module (MIRM) 28 capable of receiving instructions to move orstop movement of the wheel 18 from the central command module 4. The CCM4 is a user operated control that is used to transmit instructions toeach of the apparatuses 10. The CCM 4 is capable of coordinating themovements of the apparatuses 10 to ensure that the apparatuses 10 worktogether, and do not work against each other. The movement instructionsfrom the CCM 4 may include one or both of direction or speedinstructions for the wheels 18. The movement instructions may differ foreach apparatus 10 depending on their position relative to the load to betransported. The CCM 4 may send other instructions to the apparatuses10.

The apparatus 10 is provided with a controller 30. The controller 30communicates with a transmitter module (TM) 32 and receiver module (RM)34 and the ground engaging device 16, and other components/devices ofthe apparatus 10. In particular the controller 30 is capable of sendingand receiving signals to and/or from the TM and/or RM 32, 34. This isadvantageous. For instance, communicating with the ground engagingdevice 16 enables the controller 30 to instruct the ground engagingdevice 16 to operate, thus moving the apparatus 10. It also enables thecontroller 30 to control other component parts of the apparatus 10. Forexample, if the body 12 included a support formation upon which aportion of the load is located, the controller 30 may be able to controlthe raising/lowering of the support.

The controller 30 also receives status signals from other componentsand/or devices of the apparatus 10 (e.g. battery condition, batterypower, motor(s) conditions/operation). This enables the controller 30 tobe capable of conducting a check as to the status of the componentsand/or devices of the apparatus 10, and after completing said check toprovide an “apparatus operative” or “apparatus non-operative” signal tothe transmitter module (TM) 32. Receiving status signals from componentsand/or devices of the apparatus 10 and conducting a check as to thestatus of the components and/or devices of the apparatus isadvantageous. This enables the controller 30 to determine if componentsand/or devices of the apparatus 10 are functioning correctly and if itis safe for the apparatus 10 to continue to transport the load. It alsoallows the controller 30 to send status information back to the CCM 4 toalert a user when one of the apparatus 10 has failed or may be about tofail, and what component is going to fail. This saves a user time introubleshooting what a problem may be with an apparatus 10 and allowsthe user to make the apparatus functional again more quickly than waspreviously possible. For example, if a battery powering one of theapparatus 10 is about to run out, the user can either charge the batterybefore further operation of the system 1, or switch in a spare apparatusso that the system 1 can continue to operate.

Each apparatus 10 may be provided with a display 19 for displayinginformation about the apparatus 10. For example, the display 19 may showthe battery power remaining, or it may indicate when components and/ordevices of the apparatus 10 need to be serviced. The display may alsoshow any non-critical errors that have occurred in the apparatus 10.

The TM 32 is configured to transmit, or broadcast, an “apparatusoperative” or “apparatus non-operative” signal. The RM 34 is configuredto receive from a first predetermined, or designated, other suchapparatus 10 in the system 1 its respective “apparatus operative” or“apparatus non-operative” signals. The TM 32 is, in particular,configured to transmit an “apparatus operative” or “apparatusnon-operative” signal to a RM 34 of the first, or a second,predetermined, or designated, other such apparatus 10. The TM 32 is alsoconfigured to transmit the “apparatus operative” or “apparatusnon-operative” signal to its own RM 34. Alternatively, the TM 32 isconfigured to transmit a signal that the RM 34 of the first, or asecond, predetermined, or designated, other such apparatus 10 in thesystem 1 is configured to receive. The system 1 is configured such thatthe controller 30 will only cause operation of the ground-engagingdevice 16 to move the apparatus 10 if its RM 34 has received “apparatusoperative” signal from its TM 32 and from the TM 32 of the first orsecond other such apparatus 10 in the system (in this example, one ofthe other three apparatuses 10). This is advantageous because it permitsfast and efficient shutdown of the system 1 as a whole in the event thatone of the apparatus 10 is “non-operative”. In such a situation, itmight be dangerous to continue transporting the load, so full shutdownof all of all of the apparatus in the system 1 is essential, and withina short time period. The present invention is capable of achieving afull shutdown of the system 1 within 60 ms of a fault being determinedwith one of the apparatus 10.

In the present embodiment, the controller 30 conducts a check of thestatus of the components and/or devices of the apparatus 10periodically, e.g. every 5 to 10 milliseconds. However, the check as tothe status of the components and/or devices of each apparatus 10 may,alternatively, be continuous.

In one example the controller 30 requests a status from each of thecomponents/devices of the apparatus 10. The components/devices thenreturn their status to the controller 30, so the controller 30 can thenconduct a check of the statuses to determine if an “apparatus operative”or “apparatus non-operative” signal should be sent to the TM 32. In analternative example, the components and/or devices of the apparatus 10may automatically send signals, either continuously or periodically, asto their status to the controller 30.

In the present example there are four apparatus 10 in the system 1.However, the system 1 may include a plurality of n apparatus 10, where ncan be any number greater than two. The apparatus 10 in such a system 1may be labelled A, . . . , n−1, n. It should be appreciated that theapparatus 10 in the system 1 may be labelled in any particular order andthe labelling of each apparatus 10 should not be taken to be limiting.For example a system is envisaged with apparatus A, . . . , n−1, and n,i.e. at least three apparatus 10. Each receiver module of each apparatus10 is configured to receive a first predetermined, or designated, othersuch apparatus 10 its respective “operative” or “non-operative” signals.In an example system comprising n apparatus, for instance: whenapparatus A transmits a signal it is only capable of being received bythe receiver module of apparatus n−1; when apparatus n−1 transmits asignal it is only capable of being received by the receiver module ofapparatus n; and when apparatus n transmits a signal it is only capableof being received by the receiver module of apparatus A. It should beappreciated that this order may be changed without departing from thescope of the present invention.

Additionally, the transmitter module of each apparatus 10 is configuredto transmit the “apparatus operative” or “apparatus non-operative”signal to a receiver module of the first or a second other suchapparatus 10. In the n apparatus system 1, for instance: apparatus Aonly transmits a signal to apparatus n−1; apparatus n−1 only transmits asignal to apparatus n; and apparatus n only transmits a signal toapparatus A.

The system 1 is also configured so to transmit their operative statussignals sequentially. This may be achieved by each apparatus 10 onlybeing capable of transmitting its operative status once it has receivedthe operative status of its first, or second, predetermined, ordesignated, other such apparatus 10. In a system comprising n apparatus,the system would operate as follows: apparatus A only transmits itsoperative status once the receiver module of apparatus A has receivedthe status of apparatus n; apparatus n−1 only transmits its operativestatus once the receiver module of apparatus n−1 has received the statusof apparatus A; apparatus n only transmits its operative status once thereceiver module of apparatus n has received the status of apparatus n−1.

The CCM may also receive the operative status of each of the apparatuses10 in the system 1.

In the present example, the TM 32 transmits an “apparatus operative” or“apparatus non-operative” signal to the RM 34 of the first or secondpredetermined, or designated, other such apparatus 10 in the system 1via a hard-wired connection, e.g. via wiring supported on the frame 2.The TM 32 may also transmit the “apparatus operative” or “apparatusnon-operative” signal to its own RM 34 via a hard-wired connection.However, in alternative embodiments the TM 32 may transmit an “apparatusoperative” or “apparatus non-operative” signal to the RM 34 of the firstor second predetermined, or designated, other such apparatus 10 in thesystem 1 via a wireless connection. Likewise, the TM 32 may transmit an“apparatus operative” or “apparatus non-operative” signal to its own RM34 via a wireless connection. Providing a wireless connection isadvantageous, because it permits the apparatuses 10 to be separate andmove freely from each other. It also allows an apparatus 10 to bereplaced with ease, in the event that one fails. Wireless transmissionalso means that the component/devices of the apparatus 10 can be builtinto a more compact space, as there is no longer a need to locatecomponents/devices in certain positions to enable them to communicatewith each other and/or with the controller 30.

It will be appreciated that a significant advantage of the presentinvention is that each of the apparatus 10 of the system 1 isidentical/virtually identical in shape and operation, which means thatthey can be interchanged with ease. Also, in the event that one fails, aspare such apparatus 10 can be used in any location within the system 1.All that is necessary is for the system 1 to know the location of eachapparatus 10 and this can easily be done with reference to theidentification device, such as for example an RFID device, provided onthe apparatus 10 and on the load to be transported (or on the frame 2supporting it). Thus, unlike prior art systems, the system of thepresent invention does not rely on there being a master apparatus with aplurality of slave apparatus. In such systems there is a need for theuser to have spare master and slave apparatus, which increases costssignificantly.

The method of operating the system 1 is as follows. The method includesthe step of (for each apparatus 10) conducting a check as to the statusof the components and/or devices of the apparatus 10, and aftercompleting said check providing an “apparatus operative” or “apparatusnon-operative” signal to its TM 32. Each apparatus 10 then transmits its“apparatus operative” or “apparatus non-operative” signal. Eachapparatus 10 then receives the “apparatus operative” or “apparatusnon-operative” signals from its predetermined, or designated, one of theother apparatus 10. Each apparatus 10 also receives its own “apparatusoperative” or “apparatus non-operative” signal that it transmitted. Ifone or more of the apparatuses 10 of the system 1 are in an “apparatusnon-operative” state, the controller 30 of each apparatus 10 eithershuts down its respective apparatus 10 or ceases to act on any movementinstructions received from the central command module 4.

As mentioned above, in one particular embodiment, the system 1 iscomprised of at least three apparatuses that are labelled A, . . . ,n−1, n and a CCM. Again, it should be appreciated that the apparatus 10in the system 1 may be labelled in any particular order and thelabelling of each apparatus 10 should not be taken to be limiting. Itshould also be appreciated that the use of the letter n to denote thenumber of apparatuses signifies that there could be any number ofapparatuses greater than two in the system 1. For this particularembodiment, the method includes the steps of: apparatus A transmitting asignal that is only received by or receivable by the receiver module ofapparatus n−1; apparatus n−1 transmitting a signal that is only receivedby or receivable by the receiver module of apparatus n, and apparatus ntransmitting a signal that is only received by or receivable by thereceiver module of apparatus A. It may also be the case that apparatus Aonly transmits a signal to apparatus n−1; apparatus n−1 only transmits asignal to apparatus n, and apparatus n only transmits a signal toapparatus A. It should be appreciated that the method need notnecessarily start with apparatus A transmitting a signal that is onlyreceived by apparatus n−1. The method could instead start with apparatusn transmitting a signal that is only received by apparatus A withoutdeparting from the scope of the present invention. All that is requiredis that the method includes the steps.

It has been envisaged that the system 1 will operate sequentially. Bythis we mean that an apparatus 10 is only capable of transmitting itsoperative status once it has received the operative status of its first,or second, predetermined, or designated, one of the other apparatus. Inthe particular embodiment of a system comprised of n apparatus, themethod includes the steps of: apparatus A only transmitting itsoperative status once the receiver module of apparatus A has receivedthe status of apparatus n; apparatus n−1 only transmitting its operativestatus once the receiver module of apparatus n−1 has received the statusof apparatus A, and apparatus n only transmitting its operative statusonce the receiver module of apparatus n has received the status ofapparatus n−1. Each apparatus 10 also receives its own “apparatusoperative” or “apparatus non-operative” signal either at the same time,before, or after it receives the signal from another one of theapparatuses 10.

The method may also further include the step of the central commandmodule receiving the operative statuses of each of the apparatus.

Because of the communication paths between the apparatus, if one or moreof the apparatus 10 of said system 1 are in an “apparatus non-operative”state, the controllers 30 of the apparatuses 1 effect shut down of theapparatuses 10 to ensure that the load remains in a safe position. Inthe present invention, shutdown has been achieved within a very shorttime period—around 60 ms.

The controller 30 of the respective non-operative apparatuses 10 sendsinformation relating to the status of its components and/or devices tothe CCM 4. This assists the user in identifying what the fault is ineach respective non-operative apparatus 10 to help them fix theapparatus 10, and start the system 1 running again.

The controller 30 of the respective non-operative apparatuses 10 mayconduct the method steps at the same time, sending information relatingto the status of its components and/or devices to the CCM 4 to enable auser to identify the fault present before shutting the apparatus 10 downor during shut down of the apparatus 10.

When used in this specification and claims, the terms “comprises” and“comprising” and variations thereof mean that the specified features,steps or integers are included. The terms are not to be interpreted toexclude the presence of other features, steps or components.

The features disclosed in the foregoing description, or the followingclaims, or the accompanying drawings, expressed in their specific formsor in terms of a means for performing the disclosed function, or amethod or process for attaining the disclosed result, as appropriate,may, separately, or in any combination of such features, be utilised forrealising the invention in diverse forms thereof.

The invention claimed is:
 1. An apparatus for transporting a load,including: a body including a part or portion for engaging with orconnecting to a load to be transported; a ground-engaging devicesupporting the body, the ground-engaging device for effecting movementof the body over a surface; a transmitter module; a receiver module; anda controller for communicating with the transmitter and receiver modulesand the ground engaging device and for receiving status signals fromcomponents and/or devices of the apparatus, wherein the controller iscapable of conducting a check as to the status of the components and/ordevices of the apparatus, and after completing said check to provide an“apparatus operative” or “apparatus non-operative” signal to thetransmitter module, wherein the transmitter module is configured totransmit the “apparatus operative” or “apparatus non-operative” signalincluding to its own receiver module, and wherein the receiver module isconfigured to receive from a first predetermined, or designated, othersuch apparatus its respective “apparatus operative” or “apparatusnon-operative” signals.
 2. An apparatus according to claim 1 wherein thetransmitter module is configured to transmit the “apparatus operative”or “apparatus non-operative” signal to a receiver module of the first ora second other predetermined, or designated, other such apparatus.
 3. Anapparatus according to claim 1 wherein the controller will only causeoperation of the ground-engaging device to move the apparatus if thereceiver module receives “apparatus operative” signals from itstransmitter module and from the transmitter module of the first orsecond other such apparatus.
 4. An apparatus according to claim 1wherein the apparatus includes a movement instruction receiver modulecapable of receiving instructions to move or stop movement of theground-engaging device from a central command module.
 5. An apparatusaccording to claim 4 wherein the movement instructions include one orboth of direction or speed instructions of the ground-engaging device.6. An apparatus according to claim 1 wherein the apparatus includes anelectric motor for effecting translational movement of theground-engaging device over a surface.
 7. An apparatus according toclaim 1 wherein the apparatus includes a further electric motor foreffecting steering of the ground-engaging device.
 8. An apparatusaccording to claim 1 wherein the ground-engaging device includes a wheelrotatable about a substantially horizontal axis.
 9. An apparatusaccording to claim 1 wherein the controller is capable of sending andreceiving signals to and/or from the transmitter and/or receivermodules.
 10. An apparatus according to claim 1 wherein the check as tothe status of the components and/or devices of the apparatus iscontinuous or periodic.
 11. An apparatus according to claim 1 whereinthe components and/or devices of the apparatus automatically sendsignals as to their status to the controller or wherein the controllerrequests a status from each of the components and/or devices of theapparatus.
 12. An apparatus according to claim 1 wherein the transmittermodule transmits the “apparatus operative” or “apparatus non-operative”signal to a receiver module of the first or second other such apparatusvia a hard-wired connection.
 13. An apparatus according to claim 1wherein the transmitter module transmits the “apparatus operative” or“apparatus non-operative” signal to its own receiver module via ahard-wired connection.
 14. An apparatus according to claim 1 wherein thetransmitter module transmits the “apparatus operative” or “apparatusnon-operative” signal to a receiver module of the first or second othersuch apparatus via a wireless connection.
 15. An apparatus according toclaim 1 wherein the transmitter module transmits the “apparatusoperative” or “apparatus non-operative” signal to its own receivermodule via a wireless connection.
 16. A system for transporting a loadincluding at least three apparatus (A, . . . , n−1, n) each inaccordance with claim 1, and a central command module for sendingmovement instructions to move or stop movement of the ground-engagingdevice of each apparatus, wherein the receiver module of each apparatusis configured to receive from a first predetermined, or designated,other such apparatus its respective “apparatus operative” or “apparatusnon-operative” signals.
 17. A system according to claim 16 wherein,apparatus A transmits a signal which is only capable of being receivedby the receiver module of apparatus B; and wherein apparatus n−1transmits a signal which is only capable of being received by thereceiver module of apparatus n; and wherein apparatus n transmits asignal which is only capable of being received by the receiver module ofapparatus A.
 18. A system according to claim 16 wherein the transmittermodule of each apparatus is configured to transmit an “apparatusoperative” or “apparatus non-operative” signal to a receiver module ofthe first or a second predetermined, or designated, other such apparatussuch that: apparatus A only transmits a signal to apparatus n−1;apparatus n−1 only transmits a signal to apparatus n; and apparatus nonly transmits a signal to apparatus A.
 19. A system according to claim16 wherein the apparatus are configured to transmit their operativestatus signals sequentially such that: apparatus A only transmits itsoperative status once the receiver module of apparatus A has receivedthe status of apparatus n; apparatus n−1 only transmits its operativestatus once the receiver module of apparatus n−1 has received the statusof apparatus A; and apparatus n only transmits its operative status oncethe receiver module of apparatus n has received the status of apparatusn−1.
 20. A system according to claim 16 wherein the central commandmodule receives the operative status of each of the apparatus.
 21. Amethod of operating a system for transporting a load including at leastthree apparatus (A, . . . , n−1, n), each apparatus having a controller,a transmitter module, and a receiver module, and the system including acentral command module, the method including the steps of: for eachapparatus, conducting a check as to the status of the components and/ordevices of the apparatus, and after completing said check providing an“apparatus operative” or “apparatus non-operative” signal to itstransmitter module, for each apparatus, transmitting its “apparatusoperative” or “apparatus non-operative” signal, for each apparatus,receiving at its receiver module “apparatus operative” or “apparatusnon-operative” signals from a predetermined, or designated, one of theother apparatus, wherein, if one or more of the apparatus of said systemare in an “apparatus non-operative” state, the controller of eachapparatus either shuts down its respective apparatus or ceases to act onany movement instructions received from the central command module. 22.A method according to claim 21 wherein the method further includes thesteps of: apparatus A transmitting a signal that is only received by orreceivable by the receiver module of apparatus n−1; apparatus n−1transmitting a signal that is only received by or receivable by thereceiver module of apparatus n; and apparatus n transmitting a signalthat is only received by or receivable by the receiver module ofapparatus A.
 23. A method according to claim 21 wherein the methodfurther includes the steps of: apparatus A only transmitting a signal toapparatus n−1; apparatus n−1 only transmitting a signal to apparatus n;and apparatus n only transmitting a signal to apparatus A.
 24. A methodaccording to claim 21 wherein the apparatus transmit their operativestatus signals sequentially, the method including the steps of:apparatus A only transmitting its operative status once the receivermodule of apparatus A has received the status of apparatus n; apparatusn−1 only transmitting its operative status once the receiver module ofapparatus n−1 has received the status of apparatus A; and apparatus nonly transmitting its operative status once the receiver module ofapparatus n has received the status of apparatus n−1.
 25. A methodaccording to claim 21 wherein the method further includes the step offor each apparatus, receiving its own “apparatus operative” or“apparatus non-operative” signals either at the same time, before, orafter it receives the signal from another one of the apparatuses.
 26. Amethod according to claim 21 the method further including the step ofthe central command module receiving the operative statuses of each ofthe apparatus.
 27. A method according to claim 21 wherein the controllerof the respective non-operative apparatus(es) send(s) informationrelating to the status of its components and/or devices to the centralcommand module.
 28. A method according to claim 21 wherein thecontroller of the respective non-operative apparatus(es) send(s)information relating to the status of its components and/or devices tothe central command module before shut down occurs or during shut down.